www.ijecs.in
International Journal Of Engineering And Computer Science ISSN:2319-7242
Volume - 3 Issue -8 August, 2014 Page No. 7535-7539
Adaptive Data Rate Oriented Speed and Capacity
Based Vertical Handoff Algorithm
Apurva Agarwal1, Ravi Sankar Shukla2, Pradeep Kumar Keshwani3
1, 2, 3
CSE Department Invertis University,
Invertis Village, Bareilly-Lucknow N. H. -24, India
1
apurvaAgarwal2008@gmail.com
2
ravipraful@gmail.com
keshwani.pradeep@email.com 3
Abstract: In wireless cellular environment the handoff algorithm determine when the handoff will occur and at which base station.
Heterogeneous network such as UMTS, WLAN, WiMax where vertical hand off is required further challenges the cellular network. This
paper provides an adaptive multiple attribute vertical hand of algorithm which allows wireless networks to select a mobile terminal using
fuzzy logic concept. The main contribution of this paper is to propose adaptive data rate oriented speed and capacity based vertical hand of
schemes which not only considers velocity, signal strength but also considers network bandwidth utilization for achieving load balancing
named as adaptive data rate adjustment. This enables the user in achieving quality of service in heterogeneous network and provides free
moving experience. A performance study using heterogeneous network such UMTS, WLAN, WiMax, as example shows that our proposed
vertical hand off algorithm is able to determine when the hand off is required and selects the best access network that is optimized to
network conditions , quality of service requirement , user preference , service cost , mobile terminal conditions .
Keywords: Vertical handoff, heterogeneous wireless network, adaptive data rate, mobile terminal
1. INTRODUCTION
Wireless Heterogeneous network such as WiMax, (World
Wide Interoperability for Microwave Access), WLAN
(Wireless Local Area Network), UMTS (Universal Mobile
Telecommunication System) have different characteristic based
on velocity, bandwidth, load, cost etc. There is an incessant
increase in demand to support roaming between heterogeneous
network to provide better quality of service and provide user
with free moving experience.
Handoff refers to the process of transferring an ongoing call
from one channel connected to another network. The main
purpose of handoff is to avoid call termination when the phone
is moving away from the area covered by one cell and entering
the area covered by another cell. There are two types of
handoff vertical handoff and horizontal handoff. Vertical
Handoff is used to support mobility. Vertical handoff is
automatic fall over from one technology to another in order to
maintain mobility. Horizontal Handoff is quite different from
vertical handoff. Horizontal Handoff takes place between two
cells of same network. For e.g. a user moving from UMTS cell
to another UMTS cell is an example of horizontal handoff.
Vertical Handoff not only provides free movement of user but
also helps in achieving desired QOS.
In this paper, we propose Adaptive data rate oriented speed and
capacity based vertical handoff schemes. The main contribution
of this paper is based on traditional strategy of using RSS
(Received Signal Strength) combined with other network
parameters such as node velocity, bandwidth utilization, and
signal strength and user preference. The incorporation of
network parameters considering process in vertical hand off
matric, to potentially reduce packet loss and provide mobility
adaption in hand off calculation and optimization of proposed
hand off function considering user preference. In adaptive data
rate the mobile node adapts itself according to the requirement
of base station in other terms (Load Balancing). Compared to
traditional system there was load unbalancing due to unaware
network bandwidth utilization/data rate. The traditional system
lacks quality of service routing. If the bandwidth of the mobile
node is greater than that of the other network it reduces its data
rate according to the requirement of the other network. This is
known as Adaptive Data Rate. The proposed system provides
better load balancing minimizes packet loss during hand off
mechanism and tolerant hand off delay even for high speed
mobile terminal.
The simulation result which show the advantage of the
proposed algorithm. The rest of the paper is divided into
following sections: Section II describes the related work of
existing vertical hand off system algorithms. In section III
Adaptive Data Rate speed and capacity based vertical hand off
algorithm is explained in detail. The simulation results are
described in section IV. In section V we have concluded this
paper.
Apurva Agarwal1 IJECS Volume-3 Issue-8 August, 2014 Page No.7535-7539
Page 7535
2. RELATED WORK
Vertical hand off decision is triggered when there is availability
of new point of attachment or unavailability of old point of
attachment is detected. Vertical hand off algorithm is of vital
importance for heterogeneous network. In [1] the author has
proposed a Smart Decision Model to decide ‘’Best ‘’network
interface and ‘’best’’ time moment to perform hand off. A
score function is utilized in the model to make the smart
decision based on various factors such as properties of
available network interface, system information and user
preference. In [2] the author has described that Vertical handoff
occurs when a user changes association from one type of
wireless access technology to another while maintain an active
session. Much work has been done in ensuring seamless
handoff that prevents Quality of Service. In [3] the author has
proposed Vertical Handoff in Fourth Generation Multi
Network Environment. In this the author has developed new
technologies for dynamic handoff and context aware radio link
transfer. It allows user to move seamlessly within a network
while receiving a context aware services. In [4] the author has
proposed Optimization for Vertical Handoff Decision
Algorithms. It has enabled access to different technologies in
this firstly the author has discussed the concept of policy based
handoff. Secondly cost function is used to calculate target
network based on variety of user and network valued metrics.
Lastly the performance Analysis is used to find out the
significant gain in QOS and the resources can be used
efficiently from proposed optimization. The proposed
optimization has reduced operators cost and delay. In [5] the
author has proposed adaptive hard hand off algorithms which is
based on optimizing the trade of between quality of link and
rate of hand off is taken into account. Adaption means to
remain on locus of desirable operating point as system
parameters such as velocity changes. The main advantage of
adaptive hard hand off algorithm is that it reduces hand off cost
and delay. In [6] the author has proposed a pattern recognition
system for hand off algorithm. In this the author has introduced
a new algorithm to overcome the problem of traditional hand
off algorithm and to meet the challenges by using microcellular
systems. The new algorithm uses statistical pattern recognition
technique and make use of radio wave prorogation which was
not used by Traditional Hand off algorithm. The main
advantage of this algorithm is that it has reduced hand off cost,
has prevented unnecessary hand off and has accuracy trade off.
In [7] the author has proposed a multi service vertical hand off
decision algorithm. In this the author has described policy
based hand off approach and has introduced MUSE-BDA
Multiservice Vertical Hand off decision algorithm for a cost
function based vertical hand off decision algorithm. This
network has the ability to satisfy all the users’ simultaneous
request. The main advantage of this algorithm is that it satisfies
user’s requirement and avoid unnecessary hand off.
A. Block Diagram
Figure 1: Block Diagram
B. Architecture Diagram
3. ADAPTIVE DATA RATE ORIENTED
VERTICAL HANDOFF ALGORITHM
Our proposed algorithm can be divided into five parts (1)
Velocity Analysis, (2) Bandwidth Analysis and Adaptive Data
Rate Adjustment, (3) Fuzzy Logic, (4) Handoff Execution and
Decision Making, (5) Performance Evaluation
Apurva Agarwal1 IJECS Volume-3 Issue-8 August, 2014 Page No.7535-7539
Figure 2: Architecture Diagram
Page 7536
3.2. Bandwidth Analysis and Adaptive Data Rate
Adjustment
When a Mobile Terminal gets the input information it will first
check the link types and its bandwidth utilization. Since
different networks vary in coverage , the mobile terminal need
to choose a proper network which suits its bandwidth and
define three threshold of bandwidth each for a specific type of
network . In general smaller the coverage higher will be its
bandwidth utilization node threshold the network will get.
Bandwidth utilization is mapped from number ranging 1 to
100. According to these thresholds. It employs capacity
variable to denote the bandwidth value. If it is not suited for a
new point of attachment, it adjusts the data rate before sending
the request message to new point of attachment.
Figure 3: Network Model
3.1. Velocity Analysis
The system Model consist of three types of network namely
WLAN, WiMax and UMTS. L11 link denotes WLAN network,
L16 link represents WiMax network and UMTS link stands for
UMTS network. Whenever any input information is given to
Mobile Terminal, it first checks its velocity and the type of
link. The Mobile Terminal should select a proper network
according to speed as different networks have different
coverage. Three different velocity thresholds are defined for
each type of network. Coverage is directly proportional to the
velocity threshold of network. Velocity is mapped based on
their threshold ranging from 1 to 100. Moreover it employs a
ratio variable to denote the velocity value.
Figure 5: After getting mobility it will loss the RSS, now it
will search for the any other network to offer the requirement
of the mobile node
Figure 4: Base station of UMTS network is Node 0, now the
Mobile node selected in the network and it connected with the
Base station 0
3.3. Fuzzy Control
A fuzzy control system is a control system based on fuzzy logic
– a mathematical system which takes continuous values
between 0 and 1 in contrast to digital logic which operates on
discrete values of either 0 or 1. Fuzzy logic reasoning which is
approximate rather than fixed or exact value. It is necessary to
transform information into fuzzy sets. In this section we have
considered two parameters (a) Received Signal Strength (b)
Load Conditions of Candidate network. Received power
threshold is denoted by Prx. If received signal strength is
stronger than Prx, the packet will successfully be received. The
RSS is mapped in the values ranging from weak, medium,
strong. Access Point will determine the
load conditions
ranging from 0 – 100. 0 means the link is not used by any user
and 100 means link does not have any resource. One of the
important parameter is user preference. When user preference
is mapped as high it means a new link is being preferred by
user, when user preference is mapped as low it means that user
are not in a mood to perform handoff unless current link is
becoming down .
3.4. Handoff Decision and Handoff Execution
In handoff decision the transformation of input set is performed
Apurva Agarwal1 IJECS Volume-3 Issue-8 August, 2014 Page No.7535-7539
Page 7537
into fuzzy set. Sometimes handoff decision is also taken based
on IF-THEN rules. The last step of this algorithm is to perform
handoff execution. The new point of attachment will receive
request from mobile terminal. After receiving the request from
the mobile terminal the point of attachment will reserve
resource and send acknowledgment. A new connection is being
set by a mobile terminal after receiving the acknowledgment
with the new link. The mobile terminal will now send the
message of its leaving to the old point of attachment. The old
point of attachment will now release the occupied resource and
the link will be disconnected. In this way a connection is being
established by mobile terminal to new network. In this way
vertical handoff is being performed.
4. PERFORMANCE METRICS & RESULTS
Performance of the proposed approach is calculated based on
these matrices:
4.1. Handoff Time: It is the time difference between which a
handoff request is made and the time between which the
handoff is successfully completed.
Figure 7: Throughput comparison of the existing and proposed
system
Because the proposed system considers the bandwidth during
the handoff, so throughput of the proposed system increases
while increasing the simulation time.
5. CONCLUSION
Figure 6: Handoff time comparison of the existing and
proposed system
Compare to the proposed system the handoff time of the
existing system is high. In the existing system the packet
transfer does not consider bandwidth, but the proposed system
considers the bandwidth while perform handoff.
4.2. Throughput: It is the time taken for a data to reach the
destination Mobile Terminal from source node Mobile
Terminal.
Vertical handoff is very important to heterogeneous networks.
A suitable handoff algorithm can lower handoff times and
improve handoff efficiency. We propose a speed sensitive
handoff algorithm based on fuzzy control in this paper. It
considers velocity, received signal strength, load condition, and
user preference as metrics of the network selection factors. In
addition to, it includes adaptive data rate adjustment on
considering the bandwidth utilization. The simulation results
show that the new algorithm such as speed and bandwidth
utilization based vertical handover algorithm ensures better
destination network than the traditional RSS based handoff
algorithm and improves the handoff efficiency when the users
are moving at a high speed. When considering actual user
preference and network capacity, the proposed handoff
algorithm gives better performance, packet loss control, as well
as reducing unnecessary handoff times.
6. FUTURE WORK
If handoff is done without considering the direction of mobility
of the MT, it will cause the frequent handoff between cellular
networks. In future, Handoff decision should be done by
considering the mobility direction of the MT to avoid the
problem mentioned above. Hence request for handoff should
also contain the direction of the MT.
REFRENCES
[1] Ling-Jyh Chen, Tony Sun, Benny Chen, Venkatesh Rajendran,
and Mario Gerla, “A Smart Decision Model for Vertical Handoff”.
[2] Taha, Abd-Elhamid M, Hassanein, Hossam S, Mouftah, Hussein
T, “Vertical handoffs as a radio resource management tool,”
Computer Communications, Mar 25, 2008, v 31, n 5, p 950-961.
[3] Smaoui Ikram, Zarai Faouzi, Kamoun Lotfi, “Vertical handoff
management for next generation heterogeneous networks,” ITI 5th
Apurva Agarwal1 IJECS Volume-3 Issue-8 August, 2014 Page No.7535-7539
Page 7538
International Conference on Information and Communications
Technology, 2007, p 19-25.
[4] Fang Zhu and Janise McNair, “Optimizations for Vertical Handoff
Decision Algorithms”,
[5] Rajat Prakash, and Venugopal V. Veeravall, “Adaptive Hard
Handoff Algorithms”, IEEE Journal on Selected Areas in
Communications, Vol. 18, No. 11, 2000
[6] K.D Wong, C.C.Donald, “A Pattern Recognition System for
Handoff Algorithms,” IEEE Journal on Selected Areas in
Communications, 18(7), pp.1301-1311, 2000
[7] Fang Zhu and JaniseMcNair, “Multiservice Vertical Handoff
Decision Algorithms”, 2006
[8] Tawil R, Demerjian J, Pujolle G, Salazar O, ” Processing-delay
reduction during the vertical handoff decision in heterogeneous
wireless systems,” AICCSA 08 - 6th IEEE/ACS International
Conference on Computer Systems and Applications, 2008, p 381-385.
[9] Smaoui Ikram, Zarai Faouzi, Kamoun Lotfi, “Vertical handoff
management for next generation heterogeneous networks,” ITI 5 th
International Conference on Information and Communications
Technolog, 2007, p 19-25.
[10] Yang Kemeng, Gondal Iqbal, Qiu Bin, “Context aware vertical
soft handoff algorithm for heterogeneous wireless networks,” The
68th IEEE Vehicular Technology Conferencel, 2008, p 4657104.
[11] Nkansah-Gyekye Yaw, Agbinya Johnson I, ” Vertical handoff
decision algorithm for UMTS-WLAN,” The 2nd International
Conference on Wireless Broadband and Ultra Wideband
Communications, AusWireless 2007, p 4299686, 2007.
[12] Ezzouhairi A, Quintero A, Pierre S, “A fuzzy decision making
strategy for vertical handoffs,” IEEE Canadian Conference on
Electrical and Computer Engineering, Proceedings, CCECE 2008,
2008, p 583-587.
[13] Xie Shengdong, Wu Meng, “Adaptive variable threshold vertical
handoff algorithm,” 2008 IEEE International Conference Neural
Networks and Signal Processing, ICNNSP, 2008, p 366-36
Apurva Agarwal1 IJECS Volume-3 Issue-8 August, 2014 Page No.7535-7539
Page 7539